Reflector for directing light



June 24, LANG REFLECTOR FOR DIRECTING LIGHT,

Filed Jan. 25, 1925 INVEN TOR.

I Nigls Lamg 434 TTORNEYK.

Patented June 24, 1930 I i i v UNITED STATES PATENT OFFICE NIELSLANG, F CLEVELAND, OHIO REFLECTOR FOB. DIEECTING' LIGHT AppIication filed January 26, 1926. Serial No. 83,813;

My invention relates to reflectors comexceeding the maximum perimeter of the posed of a plurality of reflecting surfaces lamp, two and one-quarter times. In this oppositely inclined toward each other, demanner as many oppositely inclined surfaces signed to distribute light more ideally over can be constructed, as may be necessary to the space desired, with a smaller reflector sufficiently confine the light, or to distribute than that which would be required for like or concentrate it over the desired area of distribution of light if made otherwise. An illumination. object of the invention is to provide light Further and more specific objects, features reflectors that are substantially smaller in and advantages will more clearlyappear 10 size for any specific purpose, so that they from the detail description given below taken may be more easily concealed and more ecoin connection with the accompanying drawnomically manufactured, while a further obings which form a part of this specification ject of the invention is to permit the reflectand which illustrate the application of the ing surfaces to be at a minimum distance invention to certain forms of reflectors and 15 from the source of light, to trap every availfrom which those skilled in the art will readable light ray and. prevent waste. The inily understand the applicability of the invenvention is particularly applicable to industion in the making of other kinds and forms trial lighting and to display lighting. This of reflectors. application is a continuation in part of my Fig. 1 is a vertical section of a reflector in prior application patented April 26, 1927, the plane of its axis; 7 Patent No. 1,625,948, and my prior applica- Fig. 2 is a similar view of a reflector tion patented October 22, 1929, Patent No. designed to effect a wider distribution of 1,732,582. 7 r light;

Heretofore in constructing reflectors for Fig. 3 is a vertical section of a light resuch purposes, a continuously curved, comflector taken through one axis, which effects pounded or spiraled, peripheral surface exa'particular form of light distribution; tended laterally from the neck of the reflec- Fig. 4 is a plan view of the reflector shown tor and reached a comparatively large maxiin Fig. 3; and mum perimeter before the light emitted was Fig. 5 is a vertical section of an asymmetsufliciently confined, or projected as desired. rical reflector. i 8

Such reflectors are somewhat diflicult to Referring to the accompanying drawconceal in show-windows, etc, requiring too ings by corresponding reference characters much space where intense concentration of throughout, the numeral 6 indicates the neck light is necessary and due to their bulk are of the reflector by which the reflector is concomparatively expensive to manufacture. nected to its support, and. from this neck 6 a Reflectors constructed according to my inreflecting surface 7 is extended laterally outvention are more desirable for such purposes. ward and contoured so that the light rays In constructing a reflector according to emitted by the filament or light souce 8 the present invention for reflecting light which it intercepts, are reflected in the direcrays from an incandescent lamp, an out tions desired without passing back through wardly reflecting surface (starting at the the said filament 8. The saidsurface 7 is neck of the reflector) is extended laterally preferably terminated when it is sufficiently outward and preferably terminates before its large to permit the interior periphery of the r perimeter is two and one-quarter times that inverted and oppositely inclined surface 9 of the maximum perimeter of the lamp. to clear the lamp bulb 10. The inverted sur- From this an oppositely inclined surface is face 9 is inclined so that all light rays it laterally disposed inwardly to a sufficient may intercept are reflected inwardly, preferextent to allow a second outwardly inclined ably to the surface 7 for subsequent reflecsurface'to be projected laterally therefrom, tion. Another reflecting surface 11 is prop eferably with ut this-m xim m p rimete j ed aterally forwa d f uc toll l that m all rays it reflects are projected outward from the reflector in the desired directions. Another inverted surface 12 is connected thereto, inclined at an angle substantially parallel to a light ray reflected from the surface 11; the interior size of the said surface 12 is large enough to permit the passage of the lamp bulb 10 in and out of the reflector. An outward reflecting surface 13, connected to the inverted surface 12, extends laterally forward so that the light emitted is confined to the space desired. The surface 13 is properly contoured to direct the light rays outwardly over the desired area.

A modification of the same method of constructing a reflector is shown in Fig. 2. This reflector is designed to effect a less concentrated distribution of light than that of Fig. 1, the focal point indicated by the light source 8 being located farther forward. T he neck 6 is tapered to clear the lamp bulb 10; the outward reflecting surface 7 and oppositely inclined surface 9 are constructed substantially like those in Fig. 1, but the outward reflecting surface 7 is continued laterally forward until it cuts off the light at the desired angle without necessitating another step. To effect the proper distribution of light, the contour necessitated results in the maximum perimeter of the surface 11 being greater than that of the surfaces 7 or 9.

Another application of this method of constructing reflectors is shown in Figs. 3 and f, in which a reflector is shown which distributes the light differently on two opposite sides of the light source, and cuts off the light emitted at different angles. In these figures an outwardly reflecting surface 14 is extended laterally forward from the neck 6, oined by an oppositely inclined surface 15 to a second outwardly inclined reflecting surface 16, which extends laterally forward to a greater extent on one side of the light source at 17 and directs the light reflected therefrom at a lesser angle than the opposite side of the said. reflecting surface at 16. Another inversely inclined surface 18 connects an outwardly. inclined surface 19 to reflecting surfaces already described, the said surface 19 being likewise extended laterally forward to a greater extent at one part thereof to project the light rays in the desired directions and. effect a particular form of light distribution. The reflecting surface 19 as shown by plan view, is widened out on one side of the reflector axis to effecta better distribution of the reflected light and provide a more ideal cutoff of the light for certain purposes.

Another type of reflector to which this construction is applicable is an asymmetrical reflector illustrated in Fig. 5, designed for specal purposes, such as illuminating walls. This reflector may be considered as having two axes, that which passes through the center of the neck 6 and that which forms the center of the reflecting surfaces 21, 22, 23 and 2 1. The neck 6 is located on one side of the center of the outwardly concave reflecting surface 20, to which an inwardly inclined surface 21 connects an outwardly inclined curved surface 22 adapted to project light rays emitted by the light source 8 out of the reflector in certain desired directions. An oppositely inclined surface 23, adapted to reflect such light rays as it may intercept to one of the said outward reflecting surfaces, connects with the surface 22 at its maximum periphery. From its minimum periphery an outwardly reflecting surface 24f extends laterally forward until the light emitted. is confined to the extent desired. By carefully compounding the curvature of the surfaces 20, 22, and 2 f, the distribution of the reflected light, when blended with the direct rays emitted outward by the lamp, will cause 'a plane paral lel to the axis of the lamp to be illuminated at a substantially uniform intensity, While the perimeters of the said surfaces 20, 22, and 24 may be made substantially equal, for a given size of reflector to effect such distribution of light. As it is essential that floors, walls, work benches, displays, and the like are illuminated with light of somewhat uniform intensity, reflectors must effect greater concentration of light rays at such parts of the said illuminated object as are furthest from the source of light. To realize such concentration, reflecting surfaces must be of varying curvature, that is, they must be accurately compounded or spiralled. In other.

words, a series of small segments of circles may be pieced together to form in a sectional view a compound curve.

In constructing a telcsceped reflector as described herein, comprising a plurality of compounded reflecting surfaces, it is preferred. to decrease the radii in shorter stepsnear the outward edge of each outwardly reflecting surface, so that inwardly inclined. surfaces suspended therefromv will not obstruct reflected light. On the other hand, it is preferred to so position the inwardly inclined surfaces as to cause any light rays that may be intercepted to be reflected to an advantageous point on an outward reflecting surface.

From the foregoing description it will be seen that by constructing a succession of opposed reflecting surfaces, any degree of light distribution or concentration may be effected without substantially enlarging the maximum perimeter of the reflector, as the maximum perimeter is substantially dependent upon the size of the lamp bulb it surrounds, whereas, the maximum perimeter of reflectors heretofore constructed are dependent upon the degree of light distribution or concentration desired. Furthermore, the outwardly reflecting surfaces comprising my reflector may be made to separately form a continuation of one another, as to the direction in which they reflect light, or they may be constructed independently of one another, so that part or all of each reflecting surface may reflect light outward in substantially the same direction. Their individual size, contour, and relation to the light source, will, of course, vary with the distribution of light required and configuration of the light source. So that in certain cases, the reflecting surfaces may individually vary in size or mean perimeter, but from the description herein given it will be readily apparent to those familiar with the art that many other forms of reflectors may be constructed according to this invention. For instance, the reflector may be made ellipt or of irregular shape to effect particular forms of light distribution or to throw elliptical or somewhat rectangular beam 0" light. Such reflectors may either be constructed throughout of oppositely inclined reflecting surfaces as described, or the opposed reflecting surfaces could be spiraled around the lamp in helical form and thus change the general direction of illumination, instead of constructing reflectors as shown in Figs. 4 and 5. It will also be understood that any or all of the individual reflecting surfaces may be partially or completely corrugated or fluted to minimize striation, which practice is well known. I believe that the connection of inwardly inclined surfaces to outwardly reflecting surfaces, alternately arranged and forming the walls of alight reflector, results in reflectors much smaller in size than reflectors heretofore constructed for general purposes, since to effect a given light distribution, the reflecting surfaces are in closer proximity to the light source and thus the length along the axis is also lessened when the light is cut off at less than ninety degrees from the lamp axis. Such reflectors are applicable to many purposes, since their relatively smaller size enables them to be enclosed within the aperture of semi-opaque glass bowls, which are in common use for general lighting and where a reflector of the usual form would be too large for such purposes. Many applications and forms of the invention will thus be apparent to those skilled in the art.

lVhile I have described my improvements in detail, in connection with certain forms and improvements thereof, I do not wish to prising a series of reflecting surfaces surrounding a common longitudinal axis and each having curvature compounded individually in the axial plane, and other reflecting surfaces, said surfaces being alternately inclined outwardly and inwardly telescopically and adapted to reflect light from the same source, whereby there may be produced a desired degree of light concentration to illuminate a predetermined area with a re flector of substantially smaller maximum perimeter than a continuous reflecting surface contoured to effect a similar distribution of outwardly reflected light.

2. A tubular shaped light reflector, comprising aseries of reflecting surfaces independently surrounding a common longitudinal axis, each of said surfaces having curvature compounded individuall in the axial and transverse planes to proc uce a desired degree of light concentration and to illuminate a predetermined area and to prevent passage of reflected light through the source of light, said reflecting surfaces being alternately arranged telescopically with one or more inwardly inclined reflecting surfaces, whereby there results a reflector of substan tially smaller maximum perimeter than a continuous reflecting surface contoured toefl'ect a similar distribution of outwardly reflected light.

3. A tubular shaped light reflector, comprising a series of reflectlng surfaces independently surrounding a common longitudinal axis, each of said surfaces having concave curvature compounded individually in the axial plane from various radial points so as to direct the light over a predetermined area with a desired degree of concentration andof such contour that at least a majority of the light rays reflected can not pass through the source of light, and said reflecting surfaces being connected together by one or more oppositely inclined reflecting surfaces, whereby there results a reflector of substantially smaller maximum perimeter than acontinuous reflecting surface contoured to effect a similar distribution oi' outwardly reflected light.

NIELS LANG. 

